Wakening alarm of confined scope



Nov. 1, 1955 J. B. HERSH 9 WAKENING ALARM OF CONF'INED SCOPE Filed Feb. 26, 1954 Tlc j.

INVENTOR JOSEPH B. Hews BY 4 ATTO NEY Patented Nov. 1, 1955 WAKENIN G ALARM F CONFINED SCOPE Joseph B. Hersh, Upper Montclair, N. J.

Application February 26, 1954, Serial No. 412,815

7 Claims. (Cl. 340388) This invention relates generally to signaling devices,

\ and has particular reference to a wakening alarm of special purpose and design.

It is a general object of the invention to provide an improved alarm device of confined scope, adapted to generate vibrations that are inaudible except to an ear placed in direct proximity to the alarm. The device is primarily intended to serve the purpose of awakening an individual sleeper without creating any sound that might disturb another sleeper in the vicinity.

A more particular object of the invention is to provide an alarm mechanism of this general kind, which is relatively simple and inexpensive in construction, and reliable in operation over long periods of use without likelihood of impairment.

A feature of the present construction resides in the employment of a vibratable plate supported peripherally in a yieldable resilient manner, in combination with an electro-magnet arranged to cause vibrations of the plate. To achieve this result the plate is composed at least in part of a material susceptible to magnetic attraction; and in the preferred embodiment of the invention the plate is composed entirely of magnetically attractable metal.

Another feature of the improved construction lies in supporting the vibratable plate at the open end of a cupshaped housing formed of soft rubber or its equivalent, the electromagnetic vibrating means being arranged on the interior of the housing in magnetically effective relation ot the plate.

I achieve these general objects and advantages, and such other objects and advantages as may hereinafter appear or be pointed out, in the manner illustratively exemplified in the accompanying drawings, in Which- Figure 1 is a perspective view of an alarm device of the present improved character, shown in association with a connector plug for an appropriate electric outlet;

Figure 2 is an enlarged cross-sectional view along the line 2-2 of Figure 1; and

Figure 3 is a plan View, partly in section, taken substantially along the line 33 of Figure 2.

The device consists essentially of a disk-like unit associated with an ordinary electric cord 11 of any desired length. While the invention is not limited to any specific dimensions, the nature of the alarm device will be more fully understood when it is pointed out that the disk-like unit 10 is intended to be placed beneath the pillow upon which the head of the sleeper rests. A unit having a thickness of something less than an inch, and a diameter of about three inches has proven to be satisfactory.

The electromagnet in the interior of the alarm unit is preferably designed to operate with an alternating current of relatively low voltage, and for most purposes I have found it satisfactory to employ a magnet energizing coil suitable for use with a six volt source of electric current. A relatively low voltage of this kind can be readily attained by providing a transformer 12 of Wellknown kind in the connecting cord 11, and I have illustratively shown how such a transformer may be provided with a pair of prongs 13 adapted to be inserted into any conventional electric outlet. It will be understood that the features of the invention, so far as they relate to the alarm mechansim, are unaffected by the nature of the source of current employed, and by the manner in which connections are made. For example, if the connecting cord 11 is to be plugged into a timing mechanism adapted itself to deliver a current of six volts or so, the special transformer 12 might be omitted.

The structural features of the invention are best illus trated in Figures 2 and 3. The housing 10 is formed of a cup-shaped element 14, of soft rubber or its equivalent, this element having a relatively flat circular base and upstanding sides or flanges, as shown. At its rim, i. e., at the open end of the housing 14, it is provided with an inwardly directed annular groove 15, and snugly fitted within this groove is the periphery of a vibratable plate 16. The plate is thus supported in a spaced relation to the base of the housing, and constitutes a Wall of the enclosed space.

The material of which the housing 14 is composed is relatively soft and yieldable, and thus its frictional engagement with the periphery of the plate 16 does not materially dampen the vibration of the plate as a Whole. While ordinary soft rubber is suitable for the purpose, any synthetic equivalent can be employed, as will be readily understood. The housing is made of a thickness suflicient-to enable it to maintain its shape and to serve as a protective enclosure for the electromagnet arranged within it. By way of example, the base of the rubber housing 14 may have a thickness of approximately A; inch or so, whereas the rim of the cup may have a radial thickness of /2 inch, possibly a little more than this.

The plate 16 is of course a relatively rigid and highly resilient material. At least a part of the plate is susceptible to magnetic attraction, and in the preferred construction the plate is composed in its entirety of a disk of ferrous metal, such as cold-rolled steel. A circular plate approximately two inches in diameter and of approximately 18-gauge thickness (about 0.05 inch) has been satisfactorily employed.

Arranged within the housing is an electromagnet in the form of a spool having a core or hub 17 and end flanges 18 and 19. The core 17 is of magnetizable metal, such as soft iron, and the flanges 18, 19 are of insulating material. The parts may be held together in any suitable way, and I have illustratively shown the opposite ends of .the core 17 of reduced diameter, these ends having been fitted through appropriate holes in the flanges 18 and 19, then upset to clench the parts together. Surrounding the core 17 is the energizing coil 20, composed preferably of enameled copper wire or its equivalent.

The electromagnet is retained in the position shown in Figure 2, with the proximate end of the core 17 in minutely spaced relation to the mid-portion of the plate 16, by a securing means that engages directly with the plate 16 itself, in the region adjacent to that upon which the core 17 acts. More particularly, it will be observed that the end flange 19 has a lateral extension 21. By means of a spacing sleeve 22 and a stud 23 the flange 19 is firmly secured to the plate 16 at a predetermined and fixed distance from the latter. The stud 23 preferably has a head 24 hearing against the flange extension 21, and a threaded part 25 engaging within a suitably tapped opening in the plate 16. Equivalent fastening means may obviously be employed for this purpose.

The flange extension 21 affords a convenient support, also, for electric connection elements 26 (Figure 3) from which Wires 27 extend to the opposite ends, respectively, of the energizing coil 20.

From the connection elements 26, wires extend to the connection cord 11. This cord passes through an opening provided for this purpose in the side of the housing 14.

In the manufacture of the device, the electromagnet is assembled first, and is then secured to the plate 16 and to the wires at the inner end of the connection cord- 11. The device is then brought into its completely assembled form by simply working the periphery of the plate 16 into the groove of the housing 14, the material of the housing being of sufficiently yieldable' kind to permit this engagement to be effected.

In use, the energization of the electromagnet coil, either by an alternating current or by an equivalent interrupted direct current, causes the plate 16 to vibrate in a relatively unrestricted manner. The minute nature of the vibrations is indicated by the fact that the air gap between the magnet core 17 and the plate 16 is preferably of the order of 0.015 inch, and that the plate 16 does not contact with the core during its vibrations. The vibrations are inaudible to persons of normal hearing except when the ear is placed into direct proximity with the device. Under such circumstances they manifest themselves as a continuous low-pitched hum which is adequate to awakena sleeper, and not unpleasantly startling.

Since the device is devoid of moving parts (except for the vibratory motions of the plate) it requires no maintenance or attention, and operates reliably over long periods of use.

It will be understood that: the details herein described and illustrated may be varied in a number of respects, by those skilled in the art, without necessarily involving a departure from the spirit and scope of the invention as expressed in the appended claims.

Having thus described my invention what I claim as new and desire to secure by Letters Patent 1's:

1. A wakening alarm of the character described comprising a cup-shaped housing of soft rubber, the rim of the housing being provided with an inwardly directed groove, a vibratable plate peripherally fitted within said groove and supported thereby in a spaced relation to the base of the housing, at least a part of said plate being susceptible to magnetic attraction, and an electromagnet within the housing in magnetically eflective relation to said plate for vibrating the latter without causing impact between the electromagnet and plate, said vibrations being inaudible to persons of normal hearing except to an ear placed in direct proximity to the alarm.

2. An alarm as defined in claim 1, said plate being composed entirely of magnetically attractable metal.

3. An alarm as defined in claim 1, said electromagnet comprising a core and a surrounding coil and being secured directly to the plate itself in a region adjacent to said core, the securing means being such as to maintain said core in minutely spaced relation to the plate part upon which it acts.

4. An alarm as defined in claim 1, said electromagnet comprising a spool whose core is of magnetizable metal and whose end flanges are of insulating material, an energizing coil wound on said spool, said spool being positioned with its axis perpendicular to the plate, the end flange furthest from the plate having an extension, and means securing said extension to the plate in a manner to retain the proximiat'e end of said core in minutely spaced relation to the plate part upon which it acts.

5. An alarm as defined in claim 4, including electric connection elements carried by said flange extension, and wires extending from said elements to the opposite ends of said coil respectively.

6. A wakening alarm of the character described comprising a cup-shaped housing of relatively soft, resilient material, the rim of the housing being provided with an inwardly-directed groove, 21 vibratable plate having its marginal edge fitted in said groove and supported thereby inwardly of the base of the housing, at least a part of the plate being susceptible to magnetic attraction, an electromagnet located within the housing between the plate and closed top of the housing and arranged in magnetically efiective relation to the plate for vibrating the plate without impact therewith, the vibrations of the plate requiring close proximity of the ear of a person of normal hearing in order to be heard.

7. A wakening alarm of the character described comprising, a cup-shaped soft rubber housing, a magneticallysusceptible plate located within and supported by the housing, and electromagnet within the housing and arranged to magnetically attract the plate, the mounting of the magnet and plate being such as to cause vibration of the plate when the magnet is energized without impacting the plate against the magnet, thereby creating vibrations audible only to the ear of a person of normal hearing when the ear is placed close to the housing.

References Cited inthe file of this patent UNITED STATES PATENTS 

